390 lines
6.8 KiB
Go
390 lines
6.8 KiB
Go
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package snowballstem
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import (
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"log"
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"strings"
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"unicode/utf8"
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)
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// Env represents the Snowball execution environment
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type Env struct {
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current string
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Cursor int
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Limit int
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LimitBackward int
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Bra int
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Ket int
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}
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// NewEnv creates a new Snowball execution environment on the provided string
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func NewEnv(val string) *Env {
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return &Env{
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current: val,
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Cursor: 0,
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Limit: len(val),
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LimitBackward: 0,
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Bra: 0,
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Ket: len(val),
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}
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}
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func (env *Env) Current() string {
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return env.current
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}
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func (env *Env) SetCurrent(s string) {
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env.current = s
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env.Cursor = 0
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env.Limit = len(s)
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env.LimitBackward = 0
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env.Bra = 0
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env.Ket = len(s)
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}
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func (env *Env) ReplaceS(bra, ket int, s string) int32 {
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adjustment := int32(len(s)) - (int32(ket) - int32(bra))
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result, _ := splitAt(env.current, bra)
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rsplit := ket
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if ket < bra {
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rsplit = bra
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}
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_, rhs := splitAt(env.current, rsplit)
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result += s
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result += rhs
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newLim := int32(env.Limit) + adjustment
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env.Limit = int(newLim)
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if env.Cursor >= ket {
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newCur := int32(env.Cursor) + adjustment
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env.Cursor = int(newCur)
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} else if env.Cursor > bra {
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env.Cursor = bra
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}
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env.current = result
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return adjustment
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}
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func (env *Env) EqS(s string) bool {
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if env.Cursor >= env.Limit {
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return false
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}
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if strings.HasPrefix(env.current[env.Cursor:], s) {
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env.Cursor += len(s)
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for !onCharBoundary(env.current, env.Cursor) {
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env.Cursor++
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}
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return true
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}
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return false
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}
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func (env *Env) EqSB(s string) bool {
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if int32(env.Cursor)-int32(env.LimitBackward) < int32(len(s)) {
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return false
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} else if !onCharBoundary(env.current, env.Cursor-len(s)) ||
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!strings.HasPrefix(env.current[env.Cursor-len(s):], s) {
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return false
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} else {
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env.Cursor -= len(s)
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return true
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}
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}
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func (env *Env) SliceFrom(s string) bool {
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bra, ket := env.Bra, env.Ket
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env.ReplaceS(bra, ket, s)
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return true
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}
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func (env *Env) NextChar() {
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env.Cursor++
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for !onCharBoundary(env.current, env.Cursor) {
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env.Cursor++
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}
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}
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func (env *Env) PrevChar() {
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env.Cursor--
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for !onCharBoundary(env.current, env.Cursor) {
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env.Cursor--
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}
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}
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func (env *Env) ByteIndexForHop(delta int32) int32 {
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if delta > 0 {
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res := env.Cursor
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for delta > 0 {
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res++
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delta--
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for res <= len(env.current) && !onCharBoundary(env.current, res) {
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res++
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}
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}
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return int32(res)
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} else if delta < 0 {
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res := env.Cursor
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for delta < 0 {
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res--
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delta++
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for res >= 0 && !onCharBoundary(env.current, res) {
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res--
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}
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}
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return int32(res)
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} else {
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return int32(env.Cursor)
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}
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}
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func (env *Env) InGrouping(chars []byte, min, max int32) bool {
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if env.Cursor >= env.Limit {
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return false
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}
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r, _ := utf8.DecodeRuneInString(env.current[env.Cursor:])
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if r != utf8.RuneError {
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if r > max || r < min {
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return false
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}
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r -= min
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if (chars[uint(r>>3)] & (0x1 << uint(r&0x7))) == 0 {
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return false
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}
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env.NextChar()
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return true
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}
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return false
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}
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func (env *Env) InGroupingB(chars []byte, min, max int32) bool {
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if env.Cursor <= env.LimitBackward {
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return false
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}
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env.PrevChar()
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r, _ := utf8.DecodeRuneInString(env.current[env.Cursor:])
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if r != utf8.RuneError {
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env.NextChar()
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if r > max || r < min {
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return false
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}
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r -= min
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if (chars[uint(r>>3)] & (0x1 << uint(r&0x7))) == 0 {
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return false
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}
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env.PrevChar()
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return true
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}
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return false
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}
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func (env *Env) OutGrouping(chars []byte, min, max int32) bool {
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if env.Cursor >= env.Limit {
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return false
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}
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r, _ := utf8.DecodeRuneInString(env.current[env.Cursor:])
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if r != utf8.RuneError {
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if r > max || r < min {
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env.NextChar()
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return true
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}
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r -= min
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if (chars[uint(r>>3)] & (0x1 << uint(r&0x7))) == 0 {
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env.NextChar()
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return true
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}
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}
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return false
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}
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func (env *Env) OutGroupingB(chars []byte, min, max int32) bool {
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if env.Cursor <= env.LimitBackward {
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return false
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}
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env.PrevChar()
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r, _ := utf8.DecodeRuneInString(env.current[env.Cursor:])
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if r != utf8.RuneError {
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env.NextChar()
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if r > max || r < min {
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env.PrevChar()
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return true
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}
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r -= min
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if (chars[uint(r>>3)] & (0x1 << uint(r&0x7))) == 0 {
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env.PrevChar()
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return true
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}
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}
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return false
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}
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func (env *Env) SliceDel() bool {
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return env.SliceFrom("")
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}
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func (env *Env) Insert(bra, ket int, s string) {
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adjustment := env.ReplaceS(bra, ket, s)
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if bra <= env.Bra {
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env.Bra = int(int32(env.Bra) + adjustment)
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}
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if bra <= env.Ket {
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env.Ket = int(int32(env.Ket) + adjustment)
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}
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}
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func (env *Env) SliceTo() string {
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return env.current[env.Bra:env.Ket]
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}
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func (env *Env) FindAmong(amongs []*Among, ctx interface{}) int32 {
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var i int32
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j := int32(len(amongs))
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c := env.Cursor
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l := env.Limit
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var commonI, commonJ int
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firstKeyInspected := false
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for {
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k := i + ((j - i) >> 1)
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var diff int32
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common := min(commonI, commonJ)
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w := amongs[k]
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for lvar := common; lvar < len(w.Str); lvar++ {
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if c+common == l {
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diff--
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break
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}
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diff = int32(env.current[c+common]) - int32(w.Str[lvar])
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if diff != 0 {
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break
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}
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common++
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}
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if diff < 0 {
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j = k
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commonJ = common
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} else {
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i = k
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commonI = common
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}
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if j-i <= 1 {
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if i > 0 {
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break
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}
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if j == i {
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break
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}
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if firstKeyInspected {
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break
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}
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firstKeyInspected = true
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}
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}
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for {
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w := amongs[i]
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if commonI >= len(w.Str) {
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env.Cursor = c + len(w.Str)
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if w.F != nil {
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res := w.F(env, ctx)
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env.Cursor = c + len(w.Str)
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if res {
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return w.B
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}
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} else {
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return w.B
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}
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}
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i = w.A
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if i < 0 {
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return 0
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}
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}
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}
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func (env *Env) FindAmongB(amongs []*Among, ctx interface{}) int32 {
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var i int32
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j := int32(len(amongs))
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c := env.Cursor
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lb := env.LimitBackward
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var commonI, commonJ int
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firstKeyInspected := false
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for {
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k := i + ((j - i) >> 1)
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diff := int32(0)
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common := min(commonI, commonJ)
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w := amongs[k]
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for lvar := len(w.Str) - int(common) - 1; lvar >= 0; lvar-- {
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if c-common == lb {
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diff--
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break
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}
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diff = int32(env.current[c-common-1]) - int32(w.Str[lvar])
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if diff != 0 {
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break
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}
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// Count up commons. But not one character but the byte width of that char
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common++
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}
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if diff < 0 {
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j = k
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commonJ = common
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} else {
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i = k
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commonI = common
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}
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if j-i <= 1 {
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if i > 0 {
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break
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}
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if j == i {
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break
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}
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if firstKeyInspected {
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break
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}
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firstKeyInspected = true
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}
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}
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for {
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w := amongs[i]
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if commonI >= len(w.Str) {
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env.Cursor = c - len(w.Str)
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if w.F != nil {
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res := w.F(env, ctx)
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env.Cursor = c - len(w.Str)
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if res {
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return w.B
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}
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} else {
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return w.B
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}
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}
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i = w.A
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if i < 0 {
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return 0
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}
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}
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}
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func (env *Env) Debug(count, lineNumber int) {
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log.Printf("snowball debug, count: %d, line: %d", count, lineNumber)
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}
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func (env *Env) Clone() *Env {
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clone := *env
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return &clone
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}
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func (env *Env) AssignTo() string {
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return env.Current()
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}
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